With the purpose to increase the efficiency and performance of gas turbine engines, for example, there is a need for turbines, which can be operated at higher temperatures as compared to conventional gas turbines. In order to meet these operational requirements, it was in the past suggested to use so-called superalloys, e.g. nickel-based superalloys, for the manufacturing of turbine blades. However, these materials are susceptible to corrosion and limited to a certain range of high temperatures. Furthermore, in the prior art, different methods for cooling the high-temperature turbine blades for example with cooling air supply have been suggested. However, with an increase in the temperatures, the amount of necessary cooling air is increased with the decrease of the overall performance and efficiency of the gas turbines. To further increase the temperature capability of turbine blades made of superalloys, ceramic thermal barrier coating (TBCs) have been suggested. However, also with such turbine blades having a ceramic coating there are limitations with regard to the range of high temperature applications and the manufacturing of them is rather complex.
Furthermore, turbine blades for high-temperature gas turbines were suggested in the past, which are realized of a ceramic materials: for example, in EP 0 712 382 B1 the use of eutectic ceramic fibers for the manufacturing of turbine blades is disclosed, in which the ceramic eutectic fibers are used to manufacture a ceramic matrix composite.
Also US 2003/0207155 A1 describes high-temperature turbine blades made of ceramic materials, in which cooling ducts are provided for cooling the turbine blades during the operation of the gas engine in high-temperature ranges.
However, these known turbine blades for high-temperature applications have the disadvantage that they require either separate cooling means, such as cooling ducts, or do not achieve the required mechanical properties, in particular a high strength to resist the increased loads in some portions or locations of such turbine blades. A further problem of known turbine blades made of ceramic materials is that they are characterized by a rather low resistance to foreign object damages. Furthermore, the above-described eutectic ceramic materials have a relatively low fracture toughness, so that the application of such ceramic materials in the realization of turbine blades and in particular the airfoil of such blades is rather limited.